Avian leukosis virus subgroup J (ALV-J) poses a significant threat to the poultry industry; yet, our understanding of its replication and pathogenic mechanisms is limited. The Ten-Eleven Translocation 2 (TET2) is an indispensable regulatory factor in active DNA demethylation and immune response regulation. This study reports a significant and time-dependent decrease in TET2 levels following ALV-J infection and shows that the reduction of TET2 protein is mediated by the autophagy pathway. Mechanistically, we found that the accumulation of the Env protein at the late stages of ALV-J infection triggers autophagy, which, in turn, causes the TET2 protein to be exported from the nucleus and subsequently degraded in the cytoplasm. Using CRISPR-Cas9 technology, we generated TET2-deficient chicken macrophages that exhibited increased susceptibility to ALV-J replication, which was reversed by TET2 overexpression. In addition, transcriptome analysis revealed that the absence of TET2 in chicken macrophages impairs the expression of numerous cytokines and innate immune-related genes, particularly those downregulated genes enriched in the RIG-I and Toll-like signaling pathways, leading to enhanced replication of ALV-J in vitro . In summary, our research identifies TET2 as an ALV-J restriction factor. However, ALV-J exploits the autophagy machinery to promote the degradation of TET2 protein, thereby disrupting the host’s innate immune responses for viral replication. IMPORTANCE: ALV-J is a carcinogenic retrovirus that plays a critical role in avian leukosis, primarily affecting chickens. Infection with ALV-J leads to decreased production performance, compromised immune function, and the development of tumors, such as myelocytoma. Currently, there are no effective treatments for ALV-J, making the control of outbreaks a significant challenge with severe economic consequences for the poultry industry. The Env protein of ALV-J has been implicated in the virus’s pathogenicity. Our study shows that ALV-J infection induces autophagy in host cells through its Env protein, leading to the autophagic degradation of TET2, a key epigenetic regulator. The loss of TET2 in macrophages results in the downregulation of innate immune-related gene expression, thereby promoting viral replication. This is the first report to elucidate the role of the ALV-J Env protein in immune suppression via TET2 autophagic degradation during ALV-J infection, providing new insights into the mechanisms of viral immune evasion.

Metformin is a widely used antidiabetic drug for the treatment of type 2 diabetes and has been recently demonstrated to possess anti-inflammatory properties via AMPK-mediated modulation of M2 macrophage activation. However, the anti-inflammatory mechanisms of metformin on inflammatory macrophages are still not fully elucidated. In this study, we found that metformin induced apoptosis in macrophages. In particular, metformin induced apoptosis of M1 macrophages, based on M1 marker genes in apoptotic macrophages. Next, we comprehensively screened metformin-responsive genes in macrophages by RNA-seq and focused on the extrinsic apoptotic signaling pathway. The G0/G1 switch 2 gene (G0S2) was robustly up-regulated by metformin in macrophages. Overexpression of G0S2 significantly induced apoptosis of macrophages in a dose-dependent manner and blunted the function of the crucial anti-apoptotic gene Bcl-2, which was significantly reduced by metformin. These findings show that metformin promoted apoptosis of macrophages, especially M1 macrophages, via G0S2 induction and provides a novel anti-inflammatory mechanism of metformin through induction of macrophage apoptosis.

To meet the demand of consumers for chicken products, poultry breeders have made improvements to chickens. However, this has led to a new problem in the modern poultry industry, namely excessive fat deposition. This study aims to understand the effects of dietary iron supplementation on fat deposition and gut microbiota in chickens. In this study, we investigated the effects of iron on the growth performance, fat deposition, and gut microbiota of silky fowl black-bone chickens. A total of 75 7-week-old silky fowl black-bone chickens were randomly divided into three groups (five replicates per group, five chickens per replicate) and fed them for 28 days using a growing diet (control group), a growing diet + 10% tallow (high-fat diet group, HFD group), and a growing diet + 10% tallow + 500 mg/kg iron (HFDFe500 group), respectively. We detected the effects of iron on the growth performance, fat deposition, and gut microbiota of silky fowl black-bone chickens using the growth performance index test, oil red O staining, and HE staining, and found that the high-fat diet significantly increased liver and serum fat deposition and liver injury, while the addition of iron to the diet could reduce the fat deposition caused by the high-fat diet and alleviate liver injury. In addition, 16S rDNA sequencing was used to compare the relative abundance of gut microbiota in the cecal contents in different feeding groups. The results showed that the high-fat diet could induce gut microbiota imbalance in chickens, while the high-iron diet reversed the gut microbiota imbalance. PICRUSt functional prediction analysis showed that dietary iron supplementation affected amino acid metabolism, energy metabolism, cofactors, and vitamin metabolism pathways. In addition, correlation analysis showed that TG was significantly associated with Firmicutes and Actinobacteriota (p < 0.05). Overall, these results revealed high dietary iron (500 mg/kg) could reduce fat deposition and affect the gut microbiota of silky fowl black-bone chickens, suggesting that iron may regulate fat deposition by influencing the gut microbiota of chickens and provides a potential avenue that prevents excessive fat deposition in chickens by adding iron to the diet.

Infection with the avian leukosis virus subgroup J (ALV-J) impairs host genes and facilitates the establishment of chronic infection and the viral life cycle. However, the involvement of long noncoding RNAs (lncRNAs) in ALV-J infection remains largely unknown. In this study, we identified a novel chicken lncRNA derived from LTR5B of the ERV-L family (namely lnc-LTR5B), which is significantly downregulated in ALV-J infected cells. lnc-LTR5B was localized in the cytoplasm and was relatively high expressed in the chicken lung and liver. Notably, the replication of ALV-J was inhibited by the overexpression of lnc-LTR5B but enhanced when lnc-LTR5B expression was knocked down. We further confirmed that lnc-LTR5B could bind to the binding immunoglobulin protein (BiP), a master regulator of endoplasmic reticulum (ER) function. Mechanistically, lnc-LTR5B serves as a competing endogenous RNA for BiP, restricting its physical availability. Upon ALV-J infection, the reduction of lnc-LTR5B released BiP, which facilitated its translocation to the cell surface. This is crucial for ALV-J entry as well as pro-survival signaling. In conclusion, we identified an endogenous retroviral LTR-activated lnc-LTR5B that is involved in regulating the cell surface translocation of BiP, and such regulatory machinery can be exploited by ALV-J to complete its life cycle and propagate.

Wenchang chicken, a specialty of Hainan, China, is celebrated for its tender texture and unique flavor. This study investigates the impact of two traditional cooking methods, SW chicken and PP chicken, on the formation of volatile organic compounds (VOCs) in Wenchang chicken. Using advanced analytical techniques, including electronic nose (E-nose), gas chromatography-mass spectrometry (GC-MS), and gas chromatography-ion mobility spectrometry (GC-IMS), we identified and compared the key flavor compounds produced by each method. Results revealed distinct differences in VOC profiles, with steamed chicken generating higher concentrations of ketones, aldehydes, and alcohols, likely due to the higher cooking temperatures, while PP chicken retained compounds sensitive to heat. The complementary capabilities of GC-MS and GC-IMS enabled a comprehensive analysis, highlighting their potential in differentiating cooking methods and assessing flavor characteristics. This study provides insights into the flavor formation mechanisms of Wenchang chicken and establishes a foundation for its industrial standardization and quality enhancement.